CCI BR-4 Primers failure to fire

[Tony1320]

YES, till proven otherwise!! Still think the rounds are too short. Been there, done that!! Make the OAL longer by pulling the bullets out a bit to keep the case head against the bolt face. Probably too late now to know for sure.

I went from .015 jump to loading the ones that didn't fire to .010 jam and still had some that didn't fire at .010 jam

Talking with cci they are confident the issue is primer seating depth

Several members of the Canadian f class team had misfires with the br4 and switched to the cci 450. I may try the br4s one more time tomorrow with my fired brass then im going to the 450s

One of the first things i checked was my firing pin protrusion i will take a measurement when i get home though.

The primers that went off have a nice firing pin mark but the ones that didn't fire have a light mark i don't know if thats because those ones have too hard of a cup? Even when firing in another rifle several times it wouldn't go off and at that point there was plenty of strike

 

[GrocMax]

Switch to 400's or other std thickness cup primers for initial fireform on narrow shoulder angle cases. There may be a whole bunch of factors contributing to a high FTF rate with new cases but that is an almost 'surefire' fix.

Could be influenced by-
Tight primer pockets (lapua), deep pocket (shoulder of primer below chamfer) + thick cup primer = anvil seated short at same force previously used.
Underlength case for chamber. Most new brass is quite short of spec.
Suboptimal firing pin energy.
Large OD firing pin.
Firing pin drag (thick lube, cold temps, interference).

Add two or three of those factors and a thick cup primer and you suddenly get a high FTF rate. Once the cases are fireformed switch back.

 

[M-61]

but is .10 gap enough to cause a fail to fire?

That's 1/10 of an inch! Is that what you measured?

 

[Tony1320]

That's 1/10 of an inch! Is that what you measured?

That was suppose to say .010

 

[Tony1320]

Switch to 400's or other std thickness cup primers for initial fireform on narrow shoulder angle cases. There may be a whole bunch of factors contributing to a high FTF rate with new cases but that is an almost 'surefire' fix.

Could be influenced by-
Tight primer pockets (lapua), deep pocket (shoulder of primer below chamfer) + thick cup primer = anvil seated short at same force previously used.
Underlength case for chamber. Most new brass is quite short of spec.
Suboptimal firing pin energy.
Large OD firing pin.
Firing pin drag (thick lube, cold temps, interference).

Add two or three of those factors and a thick cup primer and you suddenly get a high FTF rate. Once the cases are fireformed switch back.

I measured the primer seating depth on the ones that failed to fire, they all measured .008 below flush

It is a bit cold right now (46F) but I don't think it's cold enough to be an issue

Most of my brass are fireformed now so if I still get failure to fire with the BR4s I'm gonna go with its the primers

 

[M-61]

QUOTE:
"I measured the primer seating depth on the ones that failed to fire, they all measured .008 below flush

It is a bit cold right now (46F) but I don't think it's cold enough to be an issue

Most of my brass are fireformed now so if I still get failure to fire with the BR4s I'm gonna go with its the primers"


I would be sure the primers are bottomed....their depth of .008 is interesting but bottomed is what counts.

Fortunately or unfortunately the vast majority of my shooting probably is around (or colder) than 46° with those primers with no FTF

Ever try a fired case, don't bump, and be sure the primer is bottomed...see what happens?

 

[Tony1320]

QUOTE:
"I measured the primer seating depth on the ones that failed to fire, they all measured .008 below flush

It is a bit cold right now (46F) but I don't think it's cold enough to be an issue

Most of my brass are fireformed now so if I still get failure to fire with the BR4s I'm gonna go with its the primers"


I would be sure the primers are bottomed....their depth of .008 is interesting but bottomed is what counts.

Fortunately or unfortunately the vast majority of my shooting probably is around (or colder) than 46° with those primers with no FTF

Ever try a fired case, don't bump, and be sure the primer is bottomed...see what happens?

I'm fairly certain they are bottomed, I'm priming them with a bench tool now using plenty of force.

I didn't think it would be nearly cold enough to be an issue.

I'm planning to try some fired cases in the morning with no bump if I have the time

 

[Webster]

I'm fairly certain they are bottomed, I'm priming them with a bench tool now using plenty of force.

I didn't think it would be nearly cold enough to be an issue.

I'm planning to try some fired cases in the morning with no bump if I have the time

What does plenty of force mean. You may crack the primer compound wafer.

 

[Webster]

Here's a picture of fired primers on the top and failed to fire on the bottom.

The difference in firing pin indent between fired and FF is normal. The chamber pressure pushes the primer cup against the firing pin before it retracts. That's why there is a slight ridge around fired indents. Firing pin protrusion should never be a problem. Typical protrusion is .055 - .065" It cannot vary. It has to go all the way forward each time. Based on my experience I think you may be damaging the primers by seating with too much force???

Added later:
The slight ridge/crater around the primer indent may be from the primer cup slightly entering the firing pin hole?

 

[johnfred1965]

As Comrade Terry said, humor us and replace the spring.

 

[Tony1320]

What does plenty of force mean. You may crack the primer compound wafer.

Earlier in the thread I believe someone said the hand priming tool doesn't provide enough pressure. I'm using a bench priming tool now so there should be plenty of force. I just finished loading 30 rounds. I measured every shoulder and measured every primer to make sure they were all seated properly.

Should be able to hit the range in the morning

 

[rardoin]

Will you order the Gre-Tan spring before, or after, you hit the range?

 

[kvd]

Should be able to hit the range in the morning

It will be interesting to see what happens. CCI primers sure seem to highlight deficient FP spring energy. I had FTF problems with CCI 450's while fire forming 6 BRA brass and replacing the FP spring solved the problem. These spring don't wear out - not when you consider that a typical trip to the local grocery store will cycle an engines valve springs hundreds of thousands of times. Of course valve springs are heavy duty compared to FP springs but the application is much less demanding for a FP spring and if not corroded, stretched or altered should last several lifetimes. Having said that, some short springs just don't have the energy from the get go. In the case of my Borden Rimrock BR action, the short FP spring could barely generate enough force to detonate the relatively hard CCI primers. The longer BRMXD actions do not have this issue. A new, possibly heavier spring and adding some weight to the firing pin can overcome the short action issue. Also, once the case is fire formed and a nice fit in your particular chamber is achieved, there will probably not be any more failures-to-fire.

 

[hogpatrol]

It will be interesting to see what happens. CCI primers sure seem to highlight deficient FP spring energy. I had FTF problems with CCI 450's while fire forming 6 BRA brass and replacing the FP spring solved the problem. These spring don't wear out - not when you consider that a typical trip to the local grocery store will cycle an engines valve springs hundreds of thousands of times. Of course valve springs are heavy duty compared to FP springs but the application is much less demanding for a FP spring and if not corroded, stretched or altered should last several lifetimes. Having said that, some short springs just don't have the energy from the get go. In the case of my Borden Rimrock BR action, the short FP spring could barely generate enough force to detonate the relatively hard CCI primers. The longer BRMXD actions do not have this issue. A new, possibly heavier spring and adding some weight to the firing pin can overcome the short action issue. Also, once the case is fire formed and a nice fit in your particular chamber is achieved, there will probably not be any more failures-to-fire.

ALL metal fatigues. I know competitors that change their springs every year.

 

[NorCalMikie]

Also, once the case is fire formed and a nice fit in your particular chamber is achieved, there will probably not be any more failures-to-fire.

 

[rardoin]

In the case of my Borden Rimrock BR action, the short FP spring could barely generate enough force to detonate the relatively hard CCI primers. The longer BRMXD actions do not have this issue. A new, possibly heavier spring and adding some weight to the firing pin can overcome the short action issue. Also, once the case is fire formed and a nice fit in your particular chamber is achieved, there will probably not be any more failures-to-fire.

I have had issues fireforming in both a 'SA' Borden and the BRMXD with the supplied FP springs so even the longer action had an issue. I solved it with GreTan springs for both actions. The trade-off is heavier lift required to cock the action but easy to acclimate to. However, after all cases were formed for my chamber, the original spring worked fine. I still put the GreTan back in on both actions just because I like the idea of a 'killer firing pin'.

 

[kvd]

ALL metal fatigues. I know competitors that change their springs every year.

Yes - but do they actually need to. Firing pin springs are one of the least expensive parts of a rifle so why not? - cheap insurance. A spring will fatigue only if it is worked beyond its design limits and this is more common with tension springs than compression springs. A captured compression spring like a firing pin spring has little chance of fatiguing. It may not have been strong enough to start with but it would take an awful lot of shooting to wear out a firing pin spring even under heavy competition use.

 

[kvd]

I solved it with GreTan springs for both actions.

Are these the springs he sells for $5.50 for Remington short actions? May need to get a few for fire forming duties.

 

[Tony1320]

So I just fired 15 rounds and 5 failed to fire.

These are fireformed cases shoulders bumped just enough to chamber the cases and every primer was measured to .008 to .009 deep

Im done with the br4s i will try cci 450s after the weekend

 

[rardoin]

Are these the springs he sells for $5.50 for Remington short actions? May need to get a few for fire forming duties.

yes